US5631395A - Method for removing the acidic impurities contained in a vapourized stream composed by organic vapours and water - Google Patents

Method for removing the acidic impurities contained in a vapourized stream composed by organic vapours and water Download PDF

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US5631395A
US5631395A US08/456,073 US45607395A US5631395A US 5631395 A US5631395 A US 5631395A US 45607395 A US45607395 A US 45607395A US 5631395 A US5631395 A US 5631395A
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alumina
vaporized stream
weight
water
acidic impurities
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US08/456,073
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Franco Rivetti
Daniele Delledonne
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Enichem Sintesi SpA
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Enichem Sintesi SpA
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Assigned to ENICHEM SYNTHESIS S.P.A. reassignment ENICHEM SYNTHESIS S.P.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: DELLEDONNE, DANIELE, RIVETTI, FRANCO
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C68/00—Preparation of esters of carbonic or haloformic acids
    • C07C68/08—Purification; Separation; Stabilisation

Definitions

  • the present invention relates to a method for removing the acidic impurities contained in a vaporized stream consisting of organic vapours and water.
  • the present invention relates to a method for removing the acidic impurities contained in a vaporized stream consisting of an alkanol, an alkyl carbonate, water and still other organic species in minor amounts, which removal method consists in sending said stream to an adsorption reactor containing a solid adsorbent bed comprising alumina or activated charcoal.
  • a further object of the present invention is the application of said removal method to the removal of acidic impurities, more precisely hydrogen chloride, from a vaporized stream mainly containing methanol, dimethyl carbonate , water and minor amounts of other organic species, in a process for dimethyl carbonate synthesis.
  • DMC Dimethyl carbonate
  • solvent or as a fuel additive
  • DMC is an important intermediate product in the synthesis of other alkyl or aryl carbonates, useful as synthetic lubricants, solvents, monomers for polymeric materials and for preparing isocyanates, urethanes, ureas and polycarbonates.
  • the separation of reaction effluent from catalyst is usually advantageously carried out by evaporation, by taking advantage of the difference in volatility between the organic products and water on the one hand (volatiles) and the components of the catalytic system (non-volatiles) on the other hand. In that way, vapour streams are obtained which typically contain (% by weight):
  • DMC from 25% to 50%
  • the removal of acidic impurities, in particular hydrogen chloride, contained in a stream of organic vapours can only be carried out after condensing said stream, so as to obtain a liquid phase.
  • the removal of the acidic impurities, in particular hydrogen chloride can be carried out by treating said liquid phase with an alkaline or basic agent, either in solid state, or in solution (neutralization).
  • an alkaline or basic agent either in solid state, or in solution (neutralization).
  • problems arise which are associated with the precipitation of salts formed during the neutralization reaction in the operating facilities, with consequent fouling of the latter; with their separation from the process fluids and their end disposal to dump; with the decomposition of produced DMC induced by alkaline hydrolysis in case of feed of an excess amount of the alkaline or basic agent.
  • the liquid phase obtained from the condensation of the stream of organic vapours can be caused to flow above a fixed bed constituted by ionic exchange resins of cationic type.
  • ionic exchange resins of cationic type which is generally rather low, it being comprised within the range of from 4 to 5 equivalents per kg of dry resin.
  • the present Applicant has now found a method which makes it possible the acidic impurities to be removed from a vaporized organic phase, by directly operating in the vapour phase, and thus avoiding the problem of condensation of the vaporized phase into a liquid phase, in a simple and advantageous way, by using solid adsorbent beds comprising alumina or activated charcoal.
  • Such a method makes it possible the level of said acidic impurities to be reduced down to such values--anyway lower than 1 ppm--as to allow equipment made from traditional materials to be used, thus avoiding the problems connected with the use of the usual neutralization techniques as described above.
  • the use of the method according to the present invention is all the more surprising when one considers that substantial water amounts (from 2% to 6% by weight) are present in the vaporized stream because water, in larger amounts than 0.1%-0.2% by weight, is known to inhibit adsorption of acids by alumina, because water competes with them for active centres.
  • the object of the present invention is a method for removing the acidic impurities contained in a vaporized stream composed by an alkanol, an alkyl carbonate, water and other organic products in minor amounts, which method consists in sending said stream to an adsorption reactor containing a solid adsorbent bed comprising alumina or activated charcoal.
  • Solid adsorbent beds useful for the purpose of the present invention are also those comprising modified aluminas or modified activated charcoals.
  • Aluminas or modified aluminas useful for the purpose of the present invention are those which are available from the market, produced by Katalco (I.C.I.), ALCOA (Aluminum Company of America), La Roche Chemicals, Discovery Aluminas.
  • alumina or modified alumina grades useful for the purpose of the present invention are: PURASPEC® 2110, produced by Katalco, which is an alumina modified with sodium salts (sodium aluminate); A-203 Cl®, manufactured by La Roche Chemicals, which is a modified alumina with inorganic promoters; Cl-750®, produced by Discovery Aluminas, which is a modified alumina with inorganic salts; SELEXSORB® SPCL, produced by ALCOA, which is a modified alumina with inorganic promoters.
  • Activated charcoals or modified activated charcoals useful for the purpose of the present invention are those grades which are available from the market, produced by Calgon Carbon Corporation, American Norit, Degussa and Westvaco Corporation.
  • activated charcoals or modified activated charcoal grades useful for the purpose of the present invention are: CALGON Type IVP®, which is a modified activated charcoal impregnated with sodium hydroxide, produced by Calgon Carbon Corporation; DARCO®, which is an activated charcoal produced by American Norit.
  • aluminas and activated charcoals are advantageously used in pellet form, with an average size of the pellets comprised within the range of from 2 mm to 4 mm of diameter.
  • the geometry of the adsorbent bed useful for the purpose of the present invention is the usual geometry as used in industrial facilities for the absorption of acidic impurities from incondensible gases, or gas purification.
  • an adsorbent bed can be used which is contained in a reactor in which the ratio of reactor height to diameter is comprised within the range of from 3 to 20.
  • Said adsorbent beds are capable of retaining amounts of hydrogen chloride of up to 10%-14%, based on their weight.
  • the vaporized stream containing the acidic impurities such as, e.g., hydrogen chloride, is sent to the reactor containing the solid adsorbant.
  • the above said vaporized stream can possibily contain incondensible gases, such as, e.g., H 2 , CO, CO 2 and N 2 .
  • incondensible gases such as, e.g., H 2 , CO, CO 2 and N 2 .
  • the percent ratio of incondensible gases to condensible vapours is generally comprised within the range of from 0% to 90% by volume, preferably of from 0% to 70% by volume.
  • the temperature and pressure conditions under which the method is carried out are not critical.
  • the reactor containing the solid adsorbent bed is kept at a temperature comprised within the range of from 30° C. to 150° C., preferably of from 50° C. to 110° C. and under a pressure comprised within the range of from 0.1 to 50 abs. atm, preferably of from 1 to 40 abs. atm, with the proviso that the selected pair of values should be such as to prevent the vapours from condensing under the selected operating conditions.
  • the contact times are advantageously comprised within the range of from 0.3 to 30 seconds (as calculated under standard conditions), to which values of GHSV (Gas Hourly Space Velocity) correspond which are comprised within the range of from 12000 to 120 hours -1 , more preferably with contact times comprised within the range of from 0.6 to 18 seconds, to which GHSV values correspond which are comprised within the range of from 6000 to 200 hours -1 .
  • GHSV Gas Hourly Space Velocity
  • Necessary condition for method applicability is the chemical inertness of vaporized substrates versus the adsorbant.
  • the removal of any types of acidic impurities from any types of organics streams, also containing water, can be carried out by using the method according to the present invention.
  • the above said method can be used in order to remove the acidic impurities from vaporized streams containing methanol, dimethyl carbonate, water and still other organic species in minor amounts.
  • Preferred vaporized streams for the purpose of the present invention are those having the following composition (% by weight):
  • DMC from 25% to 50%
  • the method according to the present invention makes it possible the acidic impurities to be removed down to lower levels than 1 ppm by weight.
  • the process stream sent as feed to the product (DMC) purification/separation section results to be free from hydrogen chloride, with the consequent considerable advantage that for building said section, normal materials can be used without any corrosion problems and financial burdens.
  • FIG. 1 describes an apparatus used in examples.
  • FIG. 1 The apparatus used in this example is illustrated in FIG. 1.
  • Said apparatus is constituted by a peristaltic pump which delivers the feed stream to a vaporizer constituted by a glass tube coil immersed in an oil bath which is at a suitable temperature for vaporizing all feed, a preheater, the adsorption reactor containing alumina or activated charcoal, and finally a condenser with its relevant condensate collecting flask.
  • All lines connecting the several equipment pieces are of glass or teflon and are heated with an electrical heating band, so as to prevent the feed stream from getting condensed at cold spots.
  • the alumina containing reactor has a diameter of 15 mm and a variable height, ranging from 28 to 75 cm, as a function of the amount of adsorbant which one wishes to charge to it.
  • This example discloses a typical test of adsorption of hydrogen chloride contained in a vaporized feed which is caused to flow above an alumina or activated charcoal bed.
  • the apparatus used for this purpose is the same apparatus as used in Example 1, shown in FIG. 1.
  • the adsorption reactor is filled with PURASPEC® 2110 alumina in form of pellets of 5 ⁇ 8 mesh (42 ml, 34.3 g), and the reactor temperature is set at 80° C., the temperature of the vaporizer is set at 100° C. and the preheater temperature is set at 80° C.
  • a stream of 210.4 g/h is fed (GHSV of about 2800 h -1 ) of a solution having the following composition (% by weight):
  • the feed has the following composition (% by weight):
  • the purpose of this example is of verifying the adsorption degree supplied by aluminas and activated charcoals listed in following Table 2, as a function of the contact time (GHSV), with the amounts of adsorbed hydrogen chloride being expressed as % by weight based on weight on charged adsorbant.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
  • Treating Waste Gases (AREA)
  • Gas Separation By Absorption (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
US08/456,073 1994-06-03 1995-05-31 Method for removing the acidic impurities contained in a vapourized stream composed by organic vapours and water Expired - Lifetime US5631395A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITMI941159A IT1269883B (it) 1994-06-03 1994-06-03 Metodo per la rimozione dei contaminanti acidi contenuti in una corrente vaporizzata composta da vapori organici e acqua
ITMI94A1159 1994-06-03

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US5631395A true US5631395A (en) 1997-05-20

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US (1) US5631395A (no)
EP (1) EP0685452B1 (no)
JP (1) JP3796631B2 (no)
KR (1) KR0162622B1 (no)
AT (1) ATE172182T1 (no)
CA (1) CA2150868C (no)
DE (1) DE69505304T2 (no)
ES (1) ES2122437T3 (no)
IT (1) IT1269883B (no)
NO (1) NO309310B1 (no)
SA (1) SA95160137B1 (no)
ZA (1) ZA954439B (no)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110196167A1 (en) * 2010-02-09 2011-08-11 Almusaiteer Khalid A Synthesis of dimethyl carbonate from carbon dioxide and methanol

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20040014022A (ko) * 2002-08-09 2004-02-14 주식회사 세기하이텍 히트파이프의 제조방법 및 장치
TW201827395A (zh) * 2016-12-28 2018-08-01 荷蘭商蜆殼國際研究所 處理碳酸酯流之方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4218391A (en) * 1976-09-30 1980-08-19 Anic, S.P.A. Method for the preparation of esters of carbonic acid
US4318862A (en) * 1979-12-04 1982-03-09 Anic S.P.A. Process for producing dimethylcarbonate

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61210057A (ja) * 1985-12-24 1986-09-18 Tokuyama Soda Co Ltd カ−ボネ−ト化合物の精製方法
IT1248687B (it) 1990-06-04 1995-01-26 Enichem Sintesi Processo per la produzione di dimetilcarbonato ed apparecchiatura adatta allo scopo
IT1248686B (it) 1990-06-04 1995-01-26 Enichem Sintesi Procedimento per la produzione di dimetil carbonato

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4218391A (en) * 1976-09-30 1980-08-19 Anic, S.P.A. Method for the preparation of esters of carbonic acid
US4318862A (en) * 1979-12-04 1982-03-09 Anic S.P.A. Process for producing dimethylcarbonate

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Database WPI, Derwent Publications, AN 86 287960, JP A 61210057, Sep. 18, 1986. *
Database WPI, Derwent Publications, AN 86-287960, JP-A-61210057, Sep. 18, 1986.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110196167A1 (en) * 2010-02-09 2011-08-11 Almusaiteer Khalid A Synthesis of dimethyl carbonate from carbon dioxide and methanol
US9249082B2 (en) 2010-02-09 2016-02-02 King Abdulaziz City for Science and Technology (KACST) Synthesis of dimethyl carbonate from carbon dioxide and methanol

Also Published As

Publication number Publication date
JP3796631B2 (ja) 2006-07-12
ATE172182T1 (de) 1998-10-15
CA2150868C (en) 2005-04-05
KR960000287A (ko) 1996-01-25
ITMI941159A1 (it) 1995-12-03
ES2122437T3 (es) 1998-12-16
IT1269883B (it) 1997-04-15
NO952105L (no) 1995-12-04
ITMI941159A0 (it) 1994-06-03
SA95160137B1 (ar) 2006-05-13
DE69505304D1 (de) 1998-11-19
EP0685452A1 (en) 1995-12-06
NO309310B1 (no) 2001-01-15
JPH0840989A (ja) 1996-02-13
ZA954439B (en) 1996-02-05
KR0162622B1 (ko) 1998-11-16
EP0685452B1 (en) 1998-10-14
DE69505304T2 (de) 1999-05-06
NO952105D0 (no) 1995-05-29
CA2150868A1 (en) 1995-12-04

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